A battery generally includes a positive electrode (cathode), a negative electrode (anode) and an electrolyte. A battery typically includes current collectors within the electrodes that direct electrical current to the terminals of the battery. Attempts have been made to use fluids for electrodes where one or both of the electrodes are maintained in a fluid state by heating the electrode material. These batteries are sometimes referred to as thermal batteries or high-temperature batteries and include, for example, devices sometimes referred to as liquid-metal batteries and rechargeable liquid-metal batteries. Unfortunately, decades of research and development have not produced a safe and reliable thermal battery using high gravimetric energy density (kWh/kg) electrochemical couples such as, for example, sodium and sulfur or lithium and sulfur.